1. Field of the Invention
This invention relates to an article, such as a drape, worn by a patient for protection from stray radiation during laser surgery.
2. Description of the Related Art
Lasers are finding ever increasing use in medical and dental applications. They are being used by ophthalmologists, dermatologists, obstetrician/gynecologists, dentists, and others in "traditional" open surgery, endoscopic surgery, and non-surgical procedures. Lasers have found application in hemostasis, tissue welding and cutting, tissue ablation, photodynamic therapy, etc. With the increasing use of lasers in medical procedures comes a corresponding increase in the need for protection from the potentially harmful effects of stray radiation. If a laser beam that is intended to be directed to a surgical site is instead misdirected, there is risk of harm to the patient as well as to healthcare workers. The harm can be caused either directly, for example, laser-caused burns, or indirectly, if the laser beam strikes a flammable article. A number of drapes and other articles have been developed to protect against these risks.
U.S. Pat. No. 4,601,286, issued Jul. 22, 1986, to J. W. Kaufman, discloses a surgical drape for protecting healthy tissue from damage due to laser exposure during surgery. The drape comprises an adhesive-backed hydrogel layer. In another embodiment of the drape, an adhesive-backed hydrogel layer and a second layer of hydrogel sandwich a metallic sheet. In each case, the adhesive permits the drape to be adhered to the patient. Drapes of the first embodiment withstand laser exposure for only a rather short period of time. Drapes of the embodiment that include the metallic sheet tend to quickly reflect laser radiation, endangering healthcare workers.
U.S. Pat. No. 4,604,998, issued Aug. 12, 1986, to J. H. Bellina, discloses a multi-layered drape to protect a patient during laser surgery. The drape has a non-metallic layer laminated to the top, blackened surface of a first metallic layer. A second metallic layer is separated from the first metallic layer by an air gap. A laser beam enters the drape through the laminated layers and is repeatedly reflected between the facing surfaces of the two metallic layers. A shortcoming of the drape is the difficulty of maintaining the air space between the facing metallic layers.
U.S. Pat. No. 4,014,723, issued May 14, 1991, to J. W. Kaufman, discloses two-layer laser protection article that consists of a xerogel, on the side proximal to the laser beam, and a non-reflective metallic layer on the distal side. In tests, drapes made in accordance with the specification prevented potentially harmful reflection of laser radiation for only a brief period of exposure.